Digital electronic measuring devices are generally known, and there have been many suggestions for scales, readers, electronic logic circuitry and digital display devices for indicating the position of a mechanically movable probe for measurement purposes. There have also been a few suggestions for applying digital electronic measurement readout systems to handheld micrometers, but these have involved errors or deficiencies impairing the usefulness and accuracy of the instruments.
The invention involves a careful analysis of the state of the art of mechanical-optical-electronic systems for driving a digital display in response to probe movement and a realization of ways that components can be made compact enough to be included in a handheld micrometer. The invention also involves discovery of ways of mounting, orienting, and inter-relating various components to produce a handheld micrometer that is compact, portable, and inexpensive and yet highly accurate and reliable. The invention aims at substantial improvement in accuracy, efficiency, and convenience of operation in an electronic digital micrometer.